------------[ cut here ]------------
WARNING: CPU: 1 PID: 12619 at fs/namespace.c:1186 mntput_no_expire+0xade/0xcc0 fs/namespace.c:1186
Modules linked in:
CPU: 1 PID: 12619 Comm: syz-executor.0 Not tainted 5.13.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:mntput_no_expire+0xade/0xcc0 fs/namespace.c:1186
Code: ff 48 c7 c2 60 2b 79 89 be c3 02 00 00 48 c7 c7 20 2b 79 89 c6 05 6d 29 e7 0b 01 e8 93 75 0a 07 e9 3f fd ff ff e8 02 9e a6 ff <0f> 0b e9 fc fc ff ff e8 f6 9d a6 ff e8 51 93 92 ff 31 ff 89 c5 89
RSP: 0000:ffffc9000920f988 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 1ffff92001241f37 RCX: 0000000000000000
RDX: ffff888013bf8000 RSI: ffffffff81ce3dee RDI: 0000000000000003
RBP: ffff888032d1e780 R08: 0000000000000000 R09: ffffffff9026d8af
R10: ffffffff81ce3ae8 R11: 0000000000000000 R12: 0000000000000008
R13: ffffc9000920f9d8 R14: 00000000fffffff9 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2ca2b000 CR3: 0000000015be6000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 mntput fs/namespace.c:1232 [inline]
 namespace_unlock+0x26b/0x410 fs/namespace.c:1451
 drop_collected_mounts fs/namespace.c:1938 [inline]
 put_mnt_ns fs/namespace.c:4256 [inline]
 put_mnt_ns+0x106/0x140 fs/namespace.c:4252
 free_nsproxy+0x43/0x4c0 kernel/nsproxy.c:191
 put_nsproxy include/linux/nsproxy.h:105 [inline]
 switch_task_namespaces+0xaf/0xd0 kernel/nsproxy.c:249
 do_exit+0xbf7/0x2a60 kernel/exit.c:825
 do_group_exit+0x125/0x310 kernel/exit.c:923
 get_signal+0x47f/0x2150 kernel/signal.c:2835
 arch_do_signal_or_restart+0x2a8/0x1eb0 arch/x86/kernel/signal.c:789
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
 exit_to_user_mode_prepare+0x180/0x290 kernel/entry/common.c:209
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:57
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665d9
Code: Unable to access opcode bytes at RIP 0x4665af.
RSP: 002b:00007f85c2fab218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000056bf88 RCX: 00000000004665d9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000056bf88
RBP: 000000000056bf80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf8c
R13: 00007ffecde7321f R14: 00007f85c2fab300 R15: 0000000000022000